Co-Authors Plus[resolved] Since upgrading, only some roles of authors show up (4 posts)

We've got a few different user roles enabled for our website, and since upgrading to the latest version of the plugin, we're no longer able to see the majority of our users in the drop-down list that comes up when you start typing user names—just people who're of a certain level or higher.

For instance,

There are users whose levels (let's call them "Contributor Level 1") allow them to Edit Posts, Delete Posts, Read, and Upload files. They show up in the plugin when we change authors. And there's another level (let's call them "Contributor Level 2") where there is only permission to Read and Upload files—and they don't show up.

The issue is that there are other areas of the website that automatically pull in and display and manipulate users with certain role levels, and there are some contributors who we don't want to give certain permissions to (there are people who publish on our site where it's administrators who actually handle the uploading/scheduling/publishing), so simply changing roles or user levels isn't a great option.

Thanks so much for getting back to me—and, sorry, since I'm new to this sort of thing, am I editing this in the file before I upload it to the server? And what do I want to edit to make it function as it did before?